Apple mail SMTP server fails to send

My Apple mail SMTP server failed, after an Xfinity required password reset, on all my Apple devices. (iPhone, Macbook Air, iMac).

The new password works fine for send and receive on the Xfinity email website.

The SMTP server on my Apple devices shows "offline" after re-adding new password to accounts/server settings.

• First changed SMPT server password - no change, configuration wouldn't hold TLS/SSL check on. (Used TLS/SSL check on, port 465 or 587, password authentication on setup.)
• Next deleted the SMTP server and added it back with the new password - no change.  
• Removed old mail server password from keychain - no change.
• Deleted account and rebooted on one machine - now IMAP server, which worked fine with new password, fails at setup. (Xfinity account security settings are set to allow outside apps.)

Any suggestions for a fresh rebuild on the machine with deleted account or the other machines with normal functioning IMAP but no SMTP would be greatly appreciated!